Annu Yadav, Paras Yadav and Hariom Yadav
Animal Biotechnology Department, 2Animal Biochemistry
Division, National Dairy Research Institute, Karnal-132001,
Haryana, India, Email: email@example.com
Application of knowledge of fore stomach
fermentation and the use and management
of both natural and recombinant
microorganisms to improve the efficiency
of digestion of fibrous feedstuffs by
A ruminant is any hooved animal that digests its
food in two steps-
a) By eating the raw material and regurgitating a
semi digested form known as cud
b) then eating the cud, a process called
Ruminants share another common feature that
they all have an even number of toes.
Examples are: cattle, goat, sheep, camel, giraffe,
buffalo and dear etc.
Formation of food bolus
Regurgitation initiated here
Collects hardware (nails, wire)
Digestion and fermentation vat
Contains anaerobic microbes
Absorption of VFA
– muscular folds
Reduces particle size
Absorption of water
Absorption of VFA
True gastric stomach
Decreased pH from 6 to 2.5
– Denatures proteins
– Kills bacteria and pathogens
– Dissolves minerals (e.g., Ca3(PO4)2)
Many Microbial Munchers
The rumen is home to billions and billions of microbes, including
bacteria, protists, fungi, and viruses. These many different
rumen microbes form a complex community of organisms that
interact with one another, helping the animal digest its food.
Fermentation in Ruminants
Rumen is a fermentation chamber filled with
microorganisms (Gregg, 1995).
Anaerobic process-thus host can absorb energetic
by-products from bacteria fermentation.
Utilizes enzymes produced by rumen
microorganisms to digest the ingested material .
Benefits two distinguished groups: host
(ruminant) and the microorganisms.
– Large (20-200 microns) unicellular organisms
– Ingest bacteria and feed particles
– Engulf feed particles and digest carbohydrates,
proteins and fats
– Numbers affected by diet
(Yokoyama and Johnson, 1988)
– Known only for about 20 years
– Numbers usually low
– Digest recalcitrant fiber
Cellulolytic bacteria (fiber digesters)
– digest cellulose
– require pH 6-7
– utilize N in form of NH3
– require S for synthesis of sulfur-containing amino
acids (cysteine and methionine)
– produce acetate, propionate, little butyrate, CO2
– predominate from roughage diets
Amylolytic bacteria (starch, sugar digesters)
– digest starch
– require pH 5-6
– utilize N as NH3 or peptides
– produce propionate, butyrate and lactate
– predominate from grain diets
– rapid change to grain diet causes lactic acidosis
(rapidly decreases pH)
– produce methane (CH4)
– utilized by microbes for energy
– represent loss of energy to animal
– released by eructation
Improvement of Forage Quality
Reducing lignin content and increasing
fermentable carbohydrate. Increasing
Reducing concentration of secondary
compounds. (Ulyatt, 1993).
Use of exogenous fibrolytic enzymes to
improve feed utilisation.
Increasing fibre digestion.
Improving efficiency of nitrogen
Modification of ruminal ecosystems.
Recombinant ruminal Microorganisms.
Hoover and Stokes, 1991; McSweeny et al., 1994.
GI Microbes in livestock
Microbial degradation of antinutritional
Tannins Toxic Non-protein amino acids.
(Allison et al., 1985; Nelson et al., 1995)
GI Microbial enzymes In
Tannase in food, beverages, in preparation of
instant tea and as clarifier in fruit juices and beer.
Phytase as feed additives in monogastric’s foods
to increase phosphate utilisation.
Source of restriction enzymes for e.g.. Sru I and
Sru4DI from ruminal selenomonades
Lactobacillus species for disease treatment as
Future Prospect and Conclusion
Provide a natural barrier for controlling the
entry of enteric pathogens into the human
Intensive livestock production in the
In various industries apart from the
Easy and economical way to enhance
economy of developing countries.